Treatment of complex solutions of salts



All@ 29, 11933 m. LAMBERT 'ERETM'ENT [F COMPLEX SOLUTIONS 0F SALTS Filed Feb. 9. 1928 .Paiented' Aug. 29, 1933 l 1,924,503"

UNITED s'lii'rlazsv PATENT oFFlF'cE 1,924,503 TREATMENT F COMPLEX SOLUTIONS 0l" SALTS.

Arthur Lambert, New York, N. Y., assignor to Cosmic Arts, Inc., New York, N.'Y., a corporation of Delaware Application February 9, 1928. Serial- No. 253,042 1 claim. (ci. zza-ss) r/ My present invention relates to the treatment sand (glauconite, a ferruginous alkaline aluminoof complex salt solutions contalninga substansilicate of greenish color) of the following comtial'amountpf at leasttwo salts, one of which position: '(its formula being FeKSizOs-l-aq, in must be a salt of an alkali metal (sodium, powhich some iron is replaced by aluminum and tassium), or of an alkaline earth metal (barium, wherein magnesium iS SOlIlelimeS Present) 60 calcium), or of magnesium or ammonium, while f the other may be any salt different from the il'zgg; 7T-:- rst. Complex salt solutions of this type (such Ferrous oxide (1,160)"'1 '2 2 3.02 as are found, for instance, in certain natural wa- Alumina (A1203) .L 53

l0 ters and in certain industrial liquids) are sub- Lime (Cao) o 65 65 jected to the action of ammonia (whether gaseous Magnesia (Mgo) 3: 82 or liquid) and/or carbon dioxide either together Sodium oxide (Nz' `o 22 or separately, or, as an equivalent, I may employ Potssium oxide (K26"":":":':""' 7: 88 atreatment with ammonium bicarbonate.v I may, Carbon dioxide gas (005 o 15 therefore, in some cases employ carbon dioxide phosphoric anhydride (1,262)' o' 34 70 alone, and in others, ammonia alone. 'I'his states Water 8' 58 the general principle as to reagents employed. As y Y to specic applications, it will be understood that Total ma 89 even a single alkali metal salt in complex solution, 7

that is to say, accompanied by one or more other Of such greensand WI. took one kilogram, dryl 5 marketable salts of any characterwill be within and screened, and over this I poured at ordinary the scope of substances to be treated according room temperature a hydrochloric acid solution to my invention. Among the most important exprepared by diluting 100 cubic centimeters of amples of raw' materials to be subjected to my commercial hydrochloric acid having a strengthl improved process, I will mention cases where an of from 18 to 22 B., with a'sufllcient amount alkali metal salt, and particularly potassium of Water (about 4,000 cubic centimeters) to avoid chloride or potassium sulfate is found, ina natuall danger of the acid causing too sudden a geliral solution or in a liquor formed in4v the course ilcation. Some` heat is developed by the reaction o of industrial operations, associatedwwith other during. this digestion step, and when the mass had 85. "9 salts such" as aluminum salts, ,iron salts, bora'x', cooled o if, I agitated it. From two to three hours phosphates, etc. The advantages of my process were required for this digestion. lWhile the re- ,residein an increased'yield of valuable products. action proceeds satisfactorily at various tempera- Certain features.v of the. process setforth herein tures, I found that quicker and better results can have been disclosed in my earlier applications Ibe obtained at a temperature of 100 C. and I 0 "o med in the United States Patent Olce June 12th. therefore prefer this. As a resultof this step, if 1924, Serial No. 719,508, November'28th, 1924, Se- *'operatingat about 100 C., all the constituents rial No. 752,804, June 10th, 1927, Serial Number of"thelgreensand are dissolved, except the silica,` 198,007, and September 24th, 1925, Serial'l No. but if operating at ordinary room temperatureL 58,298, and, as regards subject-,matter common to there .was left undissolved, (in addition to the ,the present and Said earlier eases. my present apsilica) a certain percentage of 'the oxides of iron plication is tobe considered a continuation in and some phosphates. The silica which remains part of such. earlier cases.' in either eventhforms a sort of skeleton which ls I I` desire it to be understood that whenever the of greatl value on account loi! its adsorbent'powers liquor under treatment Contains any SQdllm S111- and moreover favors theformatlon of gelatinous 100 L 4" fate, filtration is t0 be carried out at a' temp'ia- 'c since and is well adapted for the manufacture ture of 33.3 C. i of sodium silicate. As I havefjust stated, when This improved process is applicable, among operating at ordinary room temperatureaasmall Others, to the treatment of solutions, obtained portion of the iron oxides is 'left undissolved, and

from various minerals or raw materialasuch as, for this reason I employ subsequently in such 1 5 greensand (Which COnSiSlBS largely 0f a silicate of case, an additional amount of hydrochloric acid iron a d potassium), alunite, leucite, 'feldspan (see fifth step).` Instead of hydrochloric acid, bauxitv etc. I might employ other mineral. acids, for instance vAs an examplek of my process, I will now Jdesulfuric or nitric acid. l

5,5 scribe the way in which said process vwas applied The second step consisted of a flltratiornby no f to the treatment of a specic New Jersey green-4 which the residue just specified (silica. oxides of iron) was separated from an acid yellow mother' or approved manner, `and thus recovered for industrial or other uses. Furthermore, the neutralizing treatment produces precipitates of lierric oxide, FezOs, aluminum oxide A1203, magnesium carbonate, and calcium carbonate. Finally the neutralization also produces a liquid of about from 10 to 15 B., which is an aqueous solution ofl potassium chloride Vand sodiumy chloride, so-

dium phosphate (NazHPr--12H2O), with traces of sodium carbonate. vInstead of sodium carbonate, I might employ as the neutralizing agent for this third step,`either ammonia, NH3, or ammonium bicarbonate, or as its equivalent ammonia and carbon dioxide, orothe lter liquid of the 'Solvay process, or a basev ofthe alkaline earth metals (for instance, l-lime magnesia). This modication, however, is not so desirable because I thereby forego the advantage of producing sodium carbonate as referred to hereinafter, and also les-aen vthe production of ammoniacal salts, and lose the advantageof utilizing waste heat produced during the calcining of soda and caustic soda which will always be carried out in the samel plant or works, as a natural consequence of applying my treatment to greensand which has been selected as an example. I might, of course,

40j' have chosen other raw materials as examples, for

instances, feldspar, silicates, or aluminates.

'Ihe fourth step consisted in separating the above mentioned precipitate or solid portion from the solution or liquid, as by decanting, filtration, etc. This solution is then brought'to a density of 28 B. by concentration (evaporation), or by.

adding sodium chloride or adding sodium chloride with a slightproportioh of a potassium salt (sulfate, carbonate,` chloride) The fifth step. consisted in treating the said precipitate to separatethe diiferent compounds, especially the aluminum from the iron and Vboth from the alkali earth metal salts.- For this purpose, the precipitate was mixed with water, and then lI added hydrochloric acid (of 'a strength A of from 18 to 22 B.)in the proportion of one :part of acid (by weight) to forty parts of Water. ThereuponJ added an aqueous solution of ammonia, inaan amount about'10% by volume of the combined volume of hydrochloric acid and water, that is to say, until a precipitate was obtained. .This precipitate consisted of ferric oxide and r aluminum oxide (the hydrates, FezOi and A1203) while the liquid contained in aqueous solution,

A the chlorides of magnsium, calcium, and ammonium.u If desired, this aqueous solution may be treated With'sodium carbonate, to precipitate which it is desirable to separate from the alumina, l

in order to utilize them individually in metallurgical and dyeing processes respectively,y this precipitate 'of alumina and iron oxide might be treated `with sulfuricAl acid. The resulting sul- :lates can `be separated from each other readily by crystallization. The iron sulfate thus separated could be utilized as such, or converted into f an oxide by well-known treatments. The aluminum sulfate could be used as asubstitute'ioD alum in dyeing prcesses, in accordance with the present trend of the dyeing industry.

hTe sixth step consisted in treating the filteredl tacked, remains in solution, the remainder of the potassium chloride is converted into potassium bicarbonate, which is very readily, soluble and remains in solution; a solution oi` ammonium chloride, and a precipitateof sodium bicarbonate are also formed, according to the following equation:

\NaC1+Nin+co2+H2o=NaHCo3-| (NH4) C1.

'I'here is also produced some ammonium phosphate in solution, some ammonium bicarbonate, some potassium carbonate and some free ammonia remains. f

The potassium 4chloride and the ammonium chloride are not .combined with each other, but4 form a mixture or complex solution, and canl be separated from each other by fractional crystallization. Should it be desired to use the potassium chloride as the alkali for producing a silicate, y

known or 'approved manner, to be used in theff third or neutralization step, .or Iin the production of any sodium salt according to standard methods. The ammonia also could be recovered for ,use in the process (fifth step) Instead of arnmonia and carbon dioxide, Iv may employ bicarbonate of ammonia as an equivalent.

In order to avoid loss of ammonia during the subsequent steps, whether crystallization, or sepy aration of the potassium salts, the entire mass should be converted into xed salts before evaporating the liquids, such conversion being obtained by adding a mineral acid selected according to the result desired. In the present case, for instance, hydrochloric acid would be used. y If the purpose simply vto recover free ammonia,the liquid is-heated to boiling temperature anad passed through an apparatus known in the industry as a heater or reheater. In such apparatus the free ammonia and also that of am. monium bicarbonate, are recovered readily.

The simplest procedure consists in converting the entire mass into a phosphated ammoniapotash fertilizer. Ifvthe amount of phosphoric anhydride contained in the greensand is greater than the 0.34% indicated at the beginning of this specification, the fertilizer will be all lthe better.

`Treatment of the residuary liquid with lime a solution of natural sylvinite, and may be utilized, in conjunction with'sodium nitrate or with caliche, for the production of potassium nitrate. The residual liquid or solution yields sodium chloride as a precipitate, said precipitate being impregnated with potassium nitrate, which is removed by washing with hot water. But this residual chloride which is again dissolved in the Wash water until the density of the liquid is about 24 or 25" `B., constitutes a residual liquid. By treating such liquid simultaneously with carbon r dioxide and ammonia, I obtain soda and ammoniacal salts, instead of sodium chloride alone, and thus the cost of lproduction is lowered. V

My improved process may also be applied to the treatment of other substances not previously treated in this manner. Thus it is novel to apply the treatment set forth herein, vto a solution of alunite containing potassium sulfate. Another novel application relates to the treatment of a polyphalite solution. lIn these cases, sodium sulfate and potassium nitrate are obtained. Evaporation will cause such sodium sulfate to be de' posited; it is then washed, just as was the sodium chloride in the example given above. the wash water, in which a portion of the sodium sulfate has been redissolved, is treated with carbon dio'xide and ammonia, as above, or the wash water may be added to the other liquids containing sodium chloride, the ammonia treatment being then applied to the combined liquids. In all these examples, the treatment is applied to complex salt solutions. F

The seventh step consisted in concentrating the aqueous complex solution of potassium chloride andv ammonium chloride obtained by the sixth step- (after filtration or other separation from the precipitate) Such concentration couldbe effected in various ways, for instance, (1) by evaporation in a Kestner or Swanson apparatus; (2) by the sole addition of common salt, NaCl; (3) byaddingasolutioncontaining both sodium chlo` ride and potassium chloride. If this concentration of the filtered solution be carried to the point where the density of the liquid is 28 B., such liquid becomes in effect a solution of artificial sylvinite, oneof the highest grades of potash used as a fertilizer; and if the manufacture of a fertilizer is the sole or the chief object of the process, the concentration of the liquid should be effected by means of a compound, either natural or artificial, which will increase the potash content of the product. The fertilizer will alsocontain neutral ammonium phosphate, (NH4) :PCH- 3H2O. When the liquid has been concentrated to 28 B., it may be treated with carbon dioxide and ammonia simultaneously, or with ammonium bicarbonate, or with the filtered liquid of jthe ammonia (Solvay) process, or with similar liquid. I would thus obtain, after filtration, sodium acid carbonate, ammonium chloride and potasium salts, forming together a fertilizer.

. In some cases, and especially when making fertilizers, this seventh step may take the place of the sixth step, the latter being omitted, and the concentration treatment described as the seventh step being applied directly to the filtered solution of potassium chloride and sodium chloride, etc.,

obtained by the third and fourth steps. Both steps, the sixth and seventh, in the succession named,-will be employed together if it is desired to'use the filtered liquid for purposes other than in the direct manufacture of apotash ingredient for fertilizers.

The following treatment was applied to the slids or residue obtained bythe first and second s eps.

- Such solids (insoluble in water or in acids) were mixed with sodium carbonate (NanCOa) using an amount of this salt equal to from 25 to 30 percent (by weight) of said solids or residue. I may add that a considerably smaller proportionl of sodium carbonate would be sufficient in commercial practice. The mixture was fused or melted` at a temperature of 1800". C., and then the molten mass was chilled or quenched by plunging it into cold water.` If the first step was carried out at ordinary room temperature. this fusion and chilling treatment, which may be considered as the eighth step of the process, produced carbon dioxide gas,

an aqueous solution of sodium silicate, and solids (a precipitate or residuum) consisting of anhydrous oxide of iron (FezOz) and of a small amount of free silica, the reaction being substantially represented by the equation While the solid residuum of the first step was insoluble in acids, the iron oxide forming part of the solid residuum of the eighth step is soluble in acids. The free silica found in this latter residuum is accompanied by a silica compound which I term amorphous sodio-ferric silicate, having probably the constitution:

the first step has been conducted at ordinary4 room temperature, consists of silica, amorphous sodio-ferric silicate, and anhydrous oxide of iron (FezOa). If, however, the first step was conducted at a temperature of about 100 C., the solid residuum of the eighth step will be exclusively silica. The heat absorbed by the water used for chilling during this step, may be utilized in any suitable way.

The ninth step consisted in treating the solid residuum or' precipitate (oxides of iron and.

The residue of the eighth step (anhydrous ferric oxide) was treated in the same way, in fact,

this residue and that of the fifth step might be treated together. I might, however, treat the residue of the eighth step with ammonia, NHJ, insteadof subjecting it to the treatment Just de- 1 Ii scribed as the ninth step. The-result would be substantially thesaine.

o The tentn step consisted 1n bubbling eet-bon d1- joxide gas, CO2, through the sodium .aluminate solution resulting from the ninth stepl after such f lol lsolution had been separated by filtration. This 4caused a yprecipitation 'of alumina (A1203), in raccordance with the following equation:

The products of this reaction are sodium carbonate (NazCOe) in aqueous solution, and a precipitate consisting lof aluminum hydrate, .AlzOa+aq. The solution can be separated from the precipitate in the usual ways, for instance by illtration.` The solution may be evaporated for producing sodium carbonate crystals, or may I :as

. lowing equation:

be added to the artiilcial ,sylvinite solution mentioned in connection with the sixth step.

The eleventh step consisted in the recovery of sodium carbonate, or its transformation into caustic soda, NaOH, in accordance with the fol- The calcium carbonate, CaCOa, may be usedcyclically in the operation for the purpose of causticizing the sodium carbonate, after transforma-l tioninto calcium oxide, CaO. v

Ihe accompanying drawing is a diagram or flow/sheet illustrating the example set forth above.v

y Insteadof neutralizing with sodium carbonate, as described in the third step, Iv may neutralize' the waste heat derived .l from the calcination of soda or caustic soda.

Another manner of treating the tutored uq-I uid resulting from the first and second steps, consists in mixing such liquid with caliche (impure sodium nitrate)l or with commercial sodium nitrate; the result will be the formation', by a double decomposition? of a solution of potassium nitrate and sodium chloride. By subsequent concentration sodium chloride is precipitatd, while potassium nitrate remains in solution: this compound is then obtained in solid form by evaporating the solution and eilecting crystallization. The sodium chloride (a residual product) is dissolved in water until the solution has a density of about 24 or 25 B., thus forming a residual liquid which is attacked simultaneously with carbon dioxide and ammonia for the ultimate production of the sodium carbonate used in the operation.

The examples given above relate to the treatment of greensand or of solutions obtained therefrom. As has been indicated at the beginning oi'l this specification, the invention is not restricted to treatment of greensand or of solutions o f the Y' type just referred to`. For instance, I may treat a neutral solution of alunite with carbon dioxide and ammonia, thereby precipitating alumina and a small amount .of iron. Such treatment would' result in the production of ammonium sulfate and potassium sulfate, forming (after crystallization) an ammoniacal potash fertilizer. I may also carry out the treatment with ammonia alone. Again, leucite, ieldspar, bauxite and other minerals might be treated in the same manner as above described by me in connection with greensand. V.As an alternative treatment, particularly in the case of alunite or polyhalite, I may treat the aqueous solution resulting from the third and the fourth steps described above, with sodium nitrate (NaNOa), to producek potassium nitrate (KNOs).

The general principle of my process involves the direct use of carbon dioxide or ammonia or preferably both of them (either separately or tog'ethyer) or, as an equivalent, ammonium bicarbonate, as an 'agent `or agents, to act on a solution of neutral or acid complex salts, in the form of compounds or mixtures, as obtained in nature or in the course of industrial processes, said -solution containing at least one salt of an alkali metal (sodium or potassium,) or a` salt A of an alkali earth metal (calcium, barium) or of magnesium or an ammoniacal salt. Thus a single alkali metal saltin complex solution, that other materials, such as, for instance, 1leucite,

alunite, polyhalite, feldspar, aluminous silicates, and natural waters containing sodium or potassium, also containing borates and even salts of the halogens (bromine, iodine, fluorine).

. Thus, inthe ease of en seid solution obtained from greensand, I proceed as follows:

l (a) First, leaching with a mineral acid; the residual liquid is treatedwith carbon dioxide and/ or ammonia, either separately or together, that is, I

may treat them with ammonia or ammonium bicarbonate.

(b) Instead of this, this iirst residual liquid may be treated with sodium carbonate, sodium bicarbonate, potassium carbonate or bicarbonate, ammonium bicarbonate, or calcium carbonate, barium carbonate, or magnesium carbonate, and

the resulting liquid (which .is a second residual liquid, very similar tov a solution of natural sylvinite) may be treated with carbon dioxide and/or ammonia, either separately or together.

,(c) Or the second residual liquid may be mixed with caliche or sodium nitrate to produce potassium nitrate, and the third residual liquid, containing a solution of sodium chloride only, is treated with carbon dioxide and/ or ammonia.

(d) Instead ofpotassium chloride, as in the case of greensand, the. raw material may contain potassium sulfate,'as in the case of alunite,

'KesoH-Au sooe+sn onn,

or of polyhalite, v

msoumgsoo zcasoism'o. f

If the solution obtained according to my process n either from alunite or from polyhalite is mixed with caliche or with commercial sodium nitrate,

' the residual liquid will contain sodium sulfate and will be treated simultaneously with carbon dioxide and ammonia.

(e) In the case of polyhalite, the solution obtained from this mineral may be treated directly with ammonium bicarbonate or better with sodium carbonate, and thereupon with carbon dioxide and/or ammonia. After separating the solution, calcium sulfate will be found in the filter, that is, such calcium sulfate will form part of the product indicated at A in the drawing.

Various modifications may be madewithout de 

